It is often desirable to perform positioning functions on user equipment (UE) such as a mobile terminal, a cellular phone or other mobile device. The terms “location” and “position” are synonymous and are used interchangeably herein. When the location of a UE is known, e.g. from Global Navigation Satellite Systems (GNSS) positioning, the locations of wireless Access Points (APs) that are in signal range may be estimated based on measurements of corresponding AP signals. At indoor locations or other areas where GNSS based location may be unavailable, measurements from Inertial Measurement Units (IMUs), accelerometers and other sensors on the UE may be used to determine a position of the UE. For example, based on measurements by one or more sensors, displacement from a last known GNSS determined position may be obtained. The displacement may then be used to estimate a current location of the UE and/or to estimate a location of an AP based on measurements by UEs in the vicinity.
The techniques above, however, are biased toward APs that are visible at outdoor locations, where UEs may obtain accurate GNSS positioning. IMU and/or sensor drift may limit the accuracy associated with an estimated location of a UE when GNSS signals are unavailable. Consequently, in situations where the estimated location of a UE is at least partially based on sensor measurements, estimates of AP locations based on UE measurements may also be inaccurate. For example, accuracy related to altitude (e.g. building floors) may be less than desirable. Moreover, some techniques merely report raw UE signal measurements, which may limit the utility of those measurements both by a server receiving the measurements or a UE receiving information derived from those measurements.
Techniques for the provision of contextual information in addition to UE measurements may facilitate more accurate AP and UE location determination and characterization.